Using the Poser Lens

Author: jval

Tools Needed

• Poser 3 or 4

Many Poser users never change the Poser lens focal length from its 38mm default setting. By ignoring this basic option they choose to give up substantial creative control. This illustrated article will show you the effects of different lens focal lengths and when and how to use them. Only models included with Poser are used so that you may freely duplicate and experiment with them.

But first, some basic background. The Poser lens is modelled after a real camera lens and provides the same perspective control and effects. Poser appears to use focal lengths that are very similar to a 35mm camera. Lenses are identified by their focal lengths and commonly referred to as normal, wide or telephoto lenses. The lower the focal length number, the wider the lens. Wide-angle lenses give a wide field of view and make things appear farther away. Telephoto lenses provide a narrower field and make things look closer. A normal lens is one which approximates what the human eye would see from a given position. 50-55mm would be considered a normal lens.

By using appropriate focal lengths you will be able to control various perspective and distortion effects. Such control will allow you to more accurately simulate reality or bend it to your will. The choice is yours.

The average camera snapshooter uses different lenses only for convenience, not creativity. Wide-angle lenses are used just to get it all in the picture while telephoto lenses are used because you can't get physically close enough. Depending on your scene, such real world limitations may also appear in your Poser landscape. The following images represent a single scene rendered from the same viewpoint. The only difference is the choice of lens focal length-28mm wide angle, 55mm normal and 135mm telephoto. Amateur photographers commonly use these lenses.

But lenses can also effect the way that objects appear to our eyes in respect to their relative positions and distances. This is termed perspective and is covered next.

Creative people will use their lenses differently. Instead of making subjects smaller or bigger, they will try to keep them the same size in the image view. Let's look at the same scene but with slightly different lenses. Unlike the last set of pictures, this time when we change lenses we also move our camera position closer or farther in relation to the subjects.

The 55mm length shows the expected visual relationship between the people. The gentleman is just slightly behind the lady. But notice that in the 15mm wide-angle scene there appears to be much greater distance between the two. He almost appears to be rushing to keep up with her. Also note that their faces appear distorted. This is because the distances between the right and left sides of the faces seem to be greater than they are in reality. These distortions become more pronounced towards the edges of the image. Just the opposite occurs with the 300mm telephoto lens. Now the distance between man and woman appears reduced to the point that they seem almost side by side. Things look slightly flatter.

In the real world our eyes actually see this way. But the brain knows better and makes an automatic adjustment for us so we see what we know is real. Our brains do not make this adjustment when viewing flat representational images, hence the apparent distortion.

Visual perspective is determined by three factors- the focal length of your lens, the camera position in relation to the subject and the distance between items in the field of view. Each figure is separated by a greater distance than in the previous scene. The camera position is the same in this series. The only change between images is the focal length of the lens.

Contrast the extreme depth of the 15mm image with the almost total depth absence in the 500mm view. Especially notice how the 500mm makes all figures appear approximately the same height even though each is identical and substantially behind the preceding one. Using wider or more telephoto focal lengths results in even greater perspective changes. The rate of distortion will also increase. The Poser program indicates that the focal length range is from 0.000 to 100, 000.000. It lies- the top end is 1, 000.

If there is anything with which we are intimately familiar, it is the human face. As such our tolerance for facial distortion is relatively low in matters of portraiture. Frequently portraits are limited to the facial area, known as head shots. You will recall that various focal lengths introduce their own brands of distortion. A careless choice of lenses may produce a portrait that is less than satisfactory, although the viewer may not realise quite why it is so.

In this series of images we again use the common lenses 28mm and 55mm. But this time we choose a 105mm telephoto lens, a frequent standard for photographic portraits. In each case we have moved our camera position so that the head fills approximately the same image area.

Note the severe distortion in the wide-angle picture. The nose is somewhat bulbous and the cheeks too large. The eyes recede too quickly, giving a pop-eyed appearance, and the ear appears almost flattened against the side of the head. The 55mm image is somewhat better but still echoes these distortions. It is not until the 105mm image shot that the face appears normal. The face is more gently rounded, the eyebrows appear more natural and the hair is fuller.

If you are after a natural look, your best choice for a portrait lens lies between 75mm and 105mm. But do not be afraid to use other focal lengths, especially wide angle, if you are after a special or high fashion effect.

Simple, wasn't it? Once you know what the eye expects and how it interprets perspective, you can visually lie to your artistic benefit. Try making areas appear more spacious by using the increased depth effects of the wide-angle lens. Conversely, you may make that stand of trees or a crowded room look even more densely occupied by taking advantage of the depth flattening potential of a telephoto lens.

Here are a few examples:

shelter

extreme wide-angle creates false depth

portrait of Victoria

portrait telephoto retains natural facial appearance

flutterby dreams

moderate wide-angle enhances depth and gives a sense of spaciousness